A variety of guidance systems are used in military applications. As one example, semi-active laser (SAL) designation is used in military systems to designate targets and guide a missile or other weapon to the target. In a typical SAL system, the operator of a SAL designator fires a narrow pulsed laser beam at a target. The SAL designator may be man-portable or carried by a designator aircraft such as an unmanned aerial vehicle (UAV).
The laser beam fired by the SAL designator reflects off the target to provide a reflected spot that can be detected by a SAL sensing system. When the designated target is within range, the SAL sensing system starts processing the detected returns to detect the spot, acquire the designated target and to verify that the SAL designator was the source. The SAL sensing system includes processing equipment for generating guidance commands from the pulse-stream to guide the weapon to impact.
The SAL system thus provides the ability to precisely guide weapons to a designated target. Furthermore, the SAL system provides a “man-in-the-loop” capability that is preferred in many battlefield situations.
One issue in SAL systems is the wavelength (and thus frequency) of the laser beam used to designate targets. In current implementations, SAL designators have been limited to wavelengths that are not desirable for all applications. For example, because of limitations in current SAL sensing systems, current SAL designators have been limited to wavelengths for which inexpensive commercial detectors are readily available. The availability of such detectors makes it easier for third parties to detect the use SAL designators during combat. Unwanted detection of SAL use by third parties can lead to a variety of negative outcomes.
Thus, there remains a continuing need for SAL systems in general, and SAL sensing systems in particular that can be adapted to use different radiation wavelengths. Other desirable features and characteristics of the present invention will become apparent from the subsequent Detailed Description and the appended Claims, taken in conjunction with the accompanying Drawings and this Background.